Recently, in head lamps and other lighting apparatuses, white light is generally achieved through wavelength conversion, by use of a phosphor, of blue light emitted from a light-emitting diode (LED) or a laser diode (LD).
Such a phosphor is known to be used with a resin matrix, a glass matrix, or other matrices. However, in recent years, as the output of a light source increases, the phosphor is required to have higher durability. Thus, ceramic-based phosphors have received attention (see Patent Documents 1 to 3).
A typically known ceramic phosphor is a Ce-activated garnet (A3B5O12) component, such as Y3Al5O12:Ce (YAG:Ce).